Lubricating compositions containing bis(phosphono-methyl) disulfides



3,238,131 LUBRICATING COMPOSITIQNS CUNTAINING BIS(PHGSPHON-METHYL)DISULFIDES George M. Calhoun and Hyman Diamond, Berkeley, Calif.,assignors to Shell Oil Company, New York, N.Y., a corporation ofDelaware No Drawing. Filed Dec. 23, 196i), Ser. No. 77,817 4 Claims.(Cl. 252-6237) This invention relates to improved functional organiccompositions and additives therefor. More particularly, the inventionrelates to fuel and lubricant compositions having improved stability andextreme pressure properties and additives therefor.

In general, hydrocarbon compositions are doped with various oil-solublecompounds, namely, stabilizers and antioxidants, such as phenoliccompounds, e.g., alkyl phenols and bisphenols; detergent and corrosioninhibitors which may be organic salts such as carboxylates, phenates,phosphates, sulfonates and thio-carbamates; antiwear and extremepressure compounds such as esters of fatty acids and polyhydric alcoholsor alkyl or aryl phosphites or phosphates, or free fatty acids andsulfur derivatives thereof such as C1048 fatty acids (oleic or stearicacids) and sulfurized unsaturated fatty acids, e.g., sulfurized oleicacid. However, these compounds when used in liquid hydrocarbons, such aslubricating oil compositions which are subjected to high temperaturesand pressures, break downiand fail to impart their expected desiredproperties under these extreme conditions.

It has now been discovered that liquid hydrocarbon compositions areimproved with respect to stability, wear inhibition and extreme pressureproperties, and contribute to minimizing octane requirement increasewhen used in an internal combustion engine, and the like byincorporation therein of a minor amount of an oil-soluble bis-(phosphonomethyl) disulfide having the general formula wherein the Rsare the same or different groups selected from hydrogen, hydrocarbylgroups, e.g., alkyl, aryl, aralkyl, alkaryl or cycloalkyl radicals offrom 1 to 18, preferably from 1 to 6 carbon atoms, or cationic groupssuch as metallic or non-metallic cation groups, e.g., monoor poly-valentmetal or amine, preferably alkylamine, and the Xs are independentlychalcogen atoms having an atomic number of from 8 to 16 such as oxygenor sulfur. Preferred compounds of the general formula (I) have thefollowing formula:

0 o (R10)z-CHz-SSCHg-(OR1); (II) where R is hydrogen or an alkyl radicalof from 1 to 8 carbon atoms or mixtures of hydrogen and an C alkylradical or the amine salt represented by Patented Mar. 1, 1966 where Ais an aliphatic amine, preferably a primary or secondary amine, such asC primary straight-chain amines, e.g., octylam'ine, laurylamine,stearylamine, etc., or branched-chain primary aliphatic amines, e.g.,t-C alkylam-ine, such as t-C H NH t-C H NH to t-C H NH or C secondaryaliphatic amines, such as diamylamine, di-Z-ethylhexylamine,didecylamine, etc., or the corresponding metal salts such as salts ofalkaline earth metals, e.g., Ca, Ba, Sr, or other polyvalent metals suchas Zn, Pb, Sn, Cd or Al.

The bis(methylphosphono) disulfides are prepared by reacting an alkalidisulfide, e.g., sodium or potassium disulfide, with a halomethylphosphono compound such as dihydrocarbyl ester of chloromethylphosphonicacid in a suitable solvent such as an aqueous alcoholic solution, atreflux temperature and under inert conditions until the reaction iscompleted which normally requires from 1 to about 5 days. Suitablehalomethylphosphonic compounds include monoor di-hydrocarbylchloromethylphosphonates, e.g., mono-or di-butylchloromethylphosphonate, monoor di-Z-ethylhexyl chloromethylphosphonate,monoor di-lauryl chloromethylphosphonate, monoor di-phenylchl'oromethylphosphonate, monoor di-cyclohexyl chloromethylphosphonate,monoor dibenzyl chloromethylphosphonate, dibutyldithiochloromethylphosphonate, diphenyl chloromethyl dithiophosphonate,dibutyl chloromethyltrithiophosphonate and the like.

A preferred method of making the disulfides of this invention is toreact sodium or potassium disulficle with an ester ofchloromethylphosphonic acid in an alcoholic solution under refluxconditions and under an inert atmosphere for about 24 hours andthereafter neutralizing to a pH of about 7 and ether extract and waterwashing the bis(phosphonomethyl)disulfide. The product can be used assuch or treated with a strong acid such as hydrochloric acid to springthe free acid which can be converted into desired partial or full estersor polyvalent metal salts or amine salts for use as oil, fuel and greaseadditives as Percent Percent Percent Percent O P S Found 45. 3 8. 5 14.7 11. 5 Expected 45. 1 8. 43 13. 40 12. 96

Example 11 The procedure for Example I was followed except thatmonobutyl chloromethylphosphonate was used in the reaction and the finalproduct was bis(monobutyl phosphonomethyl)disulfide Di-Z-ethylhexylaminesalt of bis(mono-butylphosphonomethyl)disulfide was prepared by reactingthe product of Example 11 with Z-ethylhexylamine in an amount sufficientto neutralize completely both acid (OH) groups, at about 50 C. in analcoholic solution and thereafter recovering the amine salt from thealcoholic solution.

Example IV Following the procedure of Example III, thetertoctadecylamine salt of the product of Example II was prepared usingtert-octadecylamine, available commercially under the trade name ofPrimene JM-T, instead of di-Z-ethylhexylamine.

The following additional bis(phosphonomethyl)disulfides illustrate theadditive of the present invention: bis- (phosphonomethyl)disulfide,bis(monooctyl phosphonomethyl)disulfide, bis(dicyclohexylphosphonomethyl)disulfide, bis(dibenzyl phosphonomethyDdisulfide,bis(diphenyl phosphonomethyl)disulfide, dioctylamine salt ofbis(monobutyl phosphonomethyl)disulfide, tert-octadecylamine salt ofbis(monobutyl phosphonomethyl)disulfide, calcium salt of bis(monobutylphosphonomethyl)disulfide and mixtures thereof.

Additional improvement of oil and fuel compositions containing the aboveaddition of the present invention, namely thebis(phosphonomethyl)disulfide, particularly with respect to oxidationand storage stability, is accomplished by addition of small amounts ofalkylated bisphenols having the general formula:

and preferably having the formula:

wherein in (V) X stands for S-, --S-S-, Se, S-CH CH SCH CHR, -CR -(CHpNH--, -O, and R stands for methyl or ethyl, n stands for an integerfrom 1 to 3; in (VI), X is CH or sulfur and R is a tertiary alkylradical. The most preferred alkylated bisphenols are represented byFormula VI, those having a sulfur bridge or, and most especially, amethylene bridge and where R is a tertiary butyl radical.

The alkylated bisphenols may contain from 1 to 8 alkyl groups, butpreferably they contain from 2 to 6 alkyl groups; alkylated bisphenolshaving 4 alkyl groups are particularly preferred. Each of the alkylgroups may contain from 1 to carbon atoms, preferably 2 to 6 carbonatoms, and especially 4 carbon atoms. Furthermore, the alkyl groups inany particular bisphenol may be the same or different and may also beprimary, sec ondary or tertiary alkyl groups. Bisphenols containing atleast one tertiary alkyl group are particularly preferred.

The alkylated bisphenol may be prepared by any of the methods known inthe art of bisphenol manufacture, for example, by selecting theappropriate alkylated phenols as starting materials and condensing themtogether by any of the established methods. For example, alkylatedbisphenols may be prepared by the method described in U.S. Patent2,944,086.

As examples of the alkylated bisphenols which may be used according tothe invention, there are mentioned his 3 -ethyl-4-hydroxyphenyl)disulfide,

bis 3-methyl-4-propyl-S-hydroxyphenyl) disulfide,

bis 2-isopropyl-3 -butyl-5-hydroxyphenyl selenide,

2,2diethyl-3-tertiary-butyl4,4'-dihydroxydiphenyl selenide,

bis 1,2 2,6-di-tertiary-butyl-4-hydroxyphenyl thiaethane,

bis 1,2 (2,5-diisopropyl-3-hydroxyphenyl) thiaethane,

bis(3,5-di-tertiary-butyl-4-hydroxyphenyl) -sulfide,

2,4-diisobutyl-3-hydroXybenZyl-2',4'-dipropyl-3 -hydroxybenzyl sulfide,

bis 1,2 3-octy1-5-tertiary-butyl-4-hydroxyphenyl) ethane,

bis 1, 1 (2,6-diisopropyl-4-hydroxyphenyl ethane,

1,2-bis (2,4-di-tertiary pentyl-3-hydroxyphenyl) propane,

bis 2,2 4,5 -di-tertiary-butyl-2-hydroxyphenyl propane,

bis Z-tertiary-butyl-5-isopentyl-4-hydroxyphenyl) amine,

bis( 3 ,5 -dibutyl-5 -hydroxypl1enyl) ether,

bis 2,6-dipropyl-4-hydroxyphenyl ether.

Preferred compounds are the alkylated bisphenols having a sulfur ormethylene bridge, the former includingbis(2,5-dipentyl-4-hydroxyphenyl)sulfide, bis(2,5-dihexyl-3-hydroxyphenyl) sulfide, bis(Z-methyl-S-tertiary butyl-4-hydroxyphenyl)sulfide, bis(Z-methyl S tertiary-butyl-6-hydroxyphenyl)sulfide and, particularly,bis(3-tertiarybutyl-S-methyl-Z-hydroxyphenyl)sulfide, and examples ofthe latter, namely, alkylated bisphenols having a methylene bridge,include bis(2,3 ditertiary-butyl 4 hydroxyphenyl)methane, bis(2,5-ditertiary butyl 4 hydroxyphenyl)methane, bis( 2,6 di tertiary butyl4-hydroxyphenyl)methane, bis(3,5 di tertiary octyl 4hydroxyphenyl)methane, bis(3-tertiary-butyl 5 tertiary-octyl-4-hydroxyphenyl)methane, and, especially,bis(3,5-di-tertiary-butyl-4-hydroxyphenyl) methane.

Also the phosphonomethyldisulfide additive, alone or in combination witha bisphenol, appears to co-act with certain phosphorus compounds to giveadditional unexpected improvement in anti-wear and anti-scuffing. Thus,this desirable improvement can be imparted to lubricants of thisinvention by also incorporating a small amount (0.01-2%, preferably0.1-1%), of a partial or full ester of an organic phosphorus compound.Phosphorus compounds of this type include alkyl, cycloalkyl, alkaryl,aralkyl, and aryl phosphites, phosphates, phosphonates, and their thioderivatives, such as C alkyl phosphites, e.g., diand tri-butyl, octyl,lauryl, stearyl, cyclohexyl, benzyl, cresyl, phenyl phosphite orphosphates, as Well as their thio derivatives; P S -pine oilreactionproduct, and metal salts thereof such as Na, K, Ca or Ba salts of P S-terpene reaction product; dibutyl methylphosphonate, dibutyltrichloromethylphosphonate, dibutyl monochloromethylphosphonate,dibutylchlorophenylphosphonate, dibutyl monochloromethylphosphonate,dibutyl chlorophenylphosphonate, and the like. The esters of pentavalentphosphorus acids such as diphenyl, dicresyl, triphenyl, tricresyl,trilauryl and tristearyl orthophosphates, P 5 terpene reaction productsand mixtures thereof are preferred.

Minor amounts of each class of additives are sufficient for a highlyeffective combination. The bis(phosphonomethyl) disulfide may be used inan amount of about 0.1-10%, preferably about 0.25% by weight, whileabout ODS-2%, preferably about 0.11%, of the methylene bisphenol orsulfide derivative thereof is highly useful and about 0.1%2% of anorganic phosphorus compound as described in the preceding paragraph.

The additives of the present invention may be used to improve varioushydrocarbon lubricating oils, whether of natural origin or synthetic,especially oils which are substantially paratiinic and/or naphthenic;these may contain substantial proportions of hydrocarbons havingaromatic character but the amounts and types of components should besuch that the Dean and Davis (Chem. and Met. Eng, vol. 36, 1929, pp.618-619) viscosity index of the base oil is at least 80, preferably to150.

The oil may be derived from a highly paratfinic crude, in which casedistillation and/ or dewaxing may be sufficient to provide a suitablebase stock; a minimum of chemical or selective solvent treatment may beused if desired. Mixed-base crudes and even highly aromatic crudes whichcontain paraffinic hydrocarbons also provide suitable base stocks bywell known refining techniques. Usually, these comprise the separationof distillate fractions of suitable boiling range followed by selec tivesolvent extraction with solvents such as furfural, phenol, and the liketo provide ratfinate fractions which are suitable for further refiningby dewaxing or chemical treatment such as sulfuric acid treatment, etc.Thus, it may be a refined hydrocarbon oil obtained from a paraffinic,naphthenic, asphaltic or mixed-base crude, and/or mixtures thereof, suchas SAE 5W, W, W, 20, 30, 40, 50 mineral oils. The hydrocarbon oils maybe blends of different mineral oil distillates and bright stock; theymay have blended therewith, in minor but compatible proportions, fixedoils, such as castor oil, lard oil and the like and/ or with syntheticlubricants, such as polymerized olefins, e.g., polyisobutylene.

The following compositions are representative of the invention:

Composition A: Percent Example I additive 2 1010 mineral oil BalanceComposition B:

Example II additive 2 1010 mineral oil Balance Composition C:

Example III additive 2 1010 mineral oil Balance Composition D:

Example IV additive 2 1010 mineral oil Balance Composition E:

Example II additive l SAE mineral oil Balance Composition F:

Example I additive 2 SAE 90 mineral oil Balance Composition G:

Example I additive 2 Bis(3,5 di tert butyl 4 hydroxyphenyl)- methane .5SAE 90 mineral oil Balance Composition H:

Example I additive 5 Ucon HB660 (polyethylene-propylene glycol having aSUS viscosity at 100 F. of 660) Balance Composition 1:

Example I additive Q 2 Di-2-ethylhexyl sebacate Balance Composition J:

Example I additive 1 Leaded gasoline (3 cc. of TEL) Balance CompositionK:

Example I additive 0.1

Fuel oil (No. 2) Balance Speed, r.p.m. 3200 Oil temperature, C 100 Oilflow-rate, cc./sec. 10 Load in increments, 5 min. at each setting.

Results of the evaluations are given in Table I and, for the purpose ofcomparison, the results obtained from theuse of the base oil alone andwith other known extreme pressure compositions are also given.

TABLE I Composition: Score load, lbs./ in. A through I 6,400 1010mineral oil+2% C alkenyl succinic acid 1,400 1010 mineral oil+2% malonicacid 2,800 1010 mineral oil+2% 3-hexadecyl adipic acid 1,400 1010mineral oil+2% dodecylmerca-ptosuccinic acid 1,400 1010 mineral oil+10%glycerol monooleate 1,800 1010 mineral oil-|-2% C13H27OH (Oxo" process)600 1.010 mineral oil 600 The following compositions were also testedfor stability in the Dornte Oxidation Test described in the NaturalPetroleum News, September 17, 1941, pages 294-6, under the followingconditions: 302 F., iron catalyst, mineral white oil base; additiveamount by weight in Other representative compositions of this inventionwhich are similarly elfective are:

(5) Mineral oil+0.15% 1,l-bis(3,5-di-tert-butyl-4-hydroxyphenyl)methane+0.15 Example I additive.

(6) Mineral oil+0.5% 1,1 bis(3,5 di tert butyl 4-hydroxyphenyl)methane-P05% Example II additive. (7) Fuel oil+0.15% 1,1bis(3,5 di tert butyl 4- hydroxyphenyl)ethane+0.15 2,6 di tert butyl 4-methylol+0.3% Example I additive.

(8) Gasoline+0.05% 1,1- bis(3 isopropyl 5 tertbutyl-4-hydroxyphenyl)methane+0.05% Example III additive.

(9) Di-Z-ethylhexyl sebacate+0.15% 1,l -bis(3-met-hyl-5-tert-butyl-4-hydroxyphenyl methane 0.15 Example IV additive.

Compositions of this invention are particularly applicable forhigh-temperature high-speed use as in aviation engines, automotiveengines and truck engines, as well as industrial equipment operatingunder the conditions described in this invention.

We claim as our invention:

1. A mineral oil composition comprising a major amount of mineral oiland from about 0.1% to about 10% of an oil-soluble bis (phosphonomethyl)disulfide having the general formula x X (RX);-PCH2SSCH2;(XR);|

where the Rs are radicals selected independently from the groupconsisting of hydrogen, C alkyl radical, and C alkylamine and X is achalcogen having an atomic number of from 8 to 16.

2. A mineral lubricating oil composition comprising a major amount ofmineral lubricating oil and from about 0.2% to about 5% of anoil-soluble bis(di-C -alkyl phosphonomethyl) disulfide.

3. A mineral lubricating oil composition comprising a major amount ofmineral lubricating oil and from about 0.2% to about 5% of bis(dibutylphosphonomet-hyDdisulfide.

4. The composition of claim 3 containing from about 0.05% to about 2% of1,1-bis(3,S-di-tert-butyl-4-hydroxyphenyl) methane.

References Cited by the Examiner UNITED STATES PATENTS 2,614,988 10/1952Hook et al 25246.6 2,725,359 11/1955 Harman et al 260461 Morris 25246.6Buck et a1 25232.7 Filbey et al.

McDermott 25246.6

Birum 260461 Birum 260-461 Hoffman 260461 Neff 25246.6

FOREIGN PATENTS Canada. Great Britain.

DANIEL E. WYMAN, Primary Examiner. 15 JULIUS GREENWALD, Examiner.

3. A MINERAL LUBRICATING OIL COMPOSITION COMRISING A MAJOR AMOUNT OFMINERAL LUBRICATING OIL AND FROM ABOUT 0.2% TRO ABOUT 5% OF BIS(DIBUTYLPHOSPHONOMETHYL)DISULFIDE.
 4. THE COMPOSITION OF CLAIM 3 CONTAINING FROMABOUT 0.05% TO ABOUT 2% OF1,1-BIS(3,5-DI-TERT-BUTYL-4-HYDROXYPHENYL)METHANE.